1. Field of the Invention
The present invention relates to an information processing device, a disc, an information processing method, and a program. More specifically, the invention relates to an information processing device, a disc, an information processing method, and a program that control access to the contents stored in an information recording medium.
2. Description of the Related Art
Discs, such as a DVD (Digital Versatile Disc) and a Blu-ray Disc (registered trademark), are used as contents recording media. For example, movie contents, and the like, are recorded in discs (for example, ROM discs) and provided for users. These disc recorded contents are mostly the contents whose copyright, distribution right, and the like, are owned by the creators or distributors. These contents are subjected to access control for preventing, for example, unauthorized copy (replication), and the like.
One of standards for contents copyright protection is AACS (Advanced Access Content System). AACS defines a copyright protection technology based on an advanced common key cryptography (AES cryptography). In the definition of the AACS, when a contents access process, such as, reproduction of contents from a disc or a contents copy recording process, is executed, it may be necessary to read identification information recorded in the disc, for example, PMSN (Pre-recorded Media Serial Number) which is disc unique identification information (media ID), and execute a process, such as authentication process or cryptography process, in accordance with a sequence defined in the AACS. For a contents storage disc according to the AACS definition, PMSN, which is disc unique identification information, is recorded in a BCA (Burst Cutting Area) of the disc.
The BCA area is different from a normal data recording area, and data are recorded by mechanical cutting, which is different from a normal data recording mode. Thus, it is difficult to rewrite recording data in the BCA area. In the reproducing process as well, a special reading process different from the normal data reproducing process may be necessary.
FIG. 1 is a view that illustrates recording data in a disc (information recording medium) 100 in which contents are recorded. The disc 100 is, for example, a DVD (Digital Versatile Disc), a Blu-ray Disc (registered trademark), or the like, and contents, such as a movie, are recorded in a data recording area.
The disc 100 includes the data recording area 110 in which contents, or the like, are recorded, and a BCA area (burst cutting area) 120 in which a media ID (for example, PMSN: Pre-recorded Media Serial Number) 121, which is disc unique identification information, is recorded.
For example, the following data are recorded in the data recording area 110 of the disc 100. The recorded data, for example, include contents 111 such as a movie, an application 112 which is a program applied to execute contents access control, such as a process of reproducing or copying the contents, and a BCA driver 113 which is a program for executing a process of reading a media ID from the BCA area 120. Note that the BCA driver 113 executes an authentication process with a drive device that reads data from the disc to thereby verify the validity of the drive device, and only when the validity of the drive device is verified, instructs the drive device to read the media ID (PMSN). The BCA driver contains a secret key 114 that is utilized in the authentication process.
A media ID (PMSN) 121, which is disc unique identification information, is recorded in the BCA area 120 of the disc 100. As described above, the BCA area is different from the normal data recording area, and data are recorded by mechanical cutting, which is different from a normal data recording mode. Thus, it is difficult to rewrite recording data in the BCA area. In the reproducing process as well, a special reading process different from the normal data reproducing process may be necessary.
According to one definition of the AACS, when the contents 111 recorded in the disc recording area 110 are copied to another media, such as a hard disk or a portable device, it may be necessary to acquire copy permission information from an external management server. To acquire the copy permission information, it may be necessary to transmit the media ID 121 to the management server.
However, the process of reaching the media ID 121 from the BCA area 120 may be executed only by the BCA driver 113 that complies with the AACS definition. The BCA driver 113 executes mutual authentication with the drive device loaded with the disc 100 in accordance with the AACS definition, verifies the validity of both the drive device and the BCA driver, reads the media ID 121, and then provides the acquired media ID to the application.
An example of this process sequence will be described with reference to FIG. 2. FIG. 2 shows the application 112 and the BCA driver 113. An information processing device, such as a PC or a reproducing device, that reproduces a disc reads and executes the application 112 and the BCA driver 113 from the disc 100.
Note that the BCA driver 113 is a program that is generated in accordance with the AACS definition, and executes an authentication process according to the AACS definition and reading of a media ID from the BCA area. On the other hand, the application 112 is a program that may be created by a third party at will. Thus, the application 112 may possibly be a malicious program, such as a program that is generated to fraudulently acquire media ID information.
The application 112 calls an API (Application Programming Interface) from the BCA driver 113. The API includes functions for requesting the BCA driver to acquire a media ID. The API is public and is available to a third party.
The BCA driver 113, in step S11, in response to the API call from the application 112, initiates a series of processes for the process of providing a media ID. First, in step S12, the BCA driver 113 executes an authentication process with the drive device that reads data from the disc to check the validity of both the drive device and the BCA driver. The authentication process is executed in accordance with the AACS definition.
In step S13, when it is not authenticated and the validity of both is not verified, an error notification is transmitted to the application 112, and the process ends without reading a media ID.
On the other hand, in step S13, when it is authenticated and the validity of both is verified, in step S14, the drive device is instructed to read a media ID from the BCA area, and the read media ID is provided to the application 112.
After that, the application 112 transmits the media ID acquired from the BCA driver 113 to the management server, and then receives contents copy permission information or other service information.
In the above series of processes, there is a problem that the application 112 is a program that may be created by a third party at will, and it may possibly be a malicious program, such as a program that is generated to fraudulently acquire media ID information. In the sequence shown in FIG. 2, even when a malicious application is used, it is easy to acquire a media ID from the BCA driver using the public API. Thus, there is a possibility that a media ID may be fraudulently acquired or contents may be fraudulently used using the fraudulently acquired media ID.